1. Field of the Invention
The field of the present invention is test equipment for optical systems. More specifically, the invention provides a system for measuring wavefront tilt in optical systems and a method of calibrating wavefront sensors.
2. Background
Presently, large optical systems exist that have apertures of approximately 1 meter or more in diameter. In the future, space based telescopes and laser beam directors are expected to have apertures in the range of 5 to 10 meters or more. Large wavefront sensors are and will be required to measure the static and/or dynamic aberrations of such large optical systems. Testing systems are especially important for space based optical systems, as careful testing on the ground before launch may greatly reducing the risk of poor performance once the optical system is in orbit. In order to test such optical systems, a wavefront sensor that is at least equal in size to the aperture of the optical system is needed. The wavefront sensor measures the wavefront tilt of light emerging from the optical system. Tilt in the wavefront of light emerging from the optical system is indicative of optical aberrations in the optical system. Once detected, the aberrations may be corrected through the addition of corrective optics, or the optical elements causing the aberrations may be replaced. Large wavefront sensors, however, are expensive and time consuming to construct.